os-collect-config ec2 collector should be treated as immutable

[Steve Baker]

Currently the ec2 collector polls the nova metadata service every $polling_period even though the data is not expected to change and no known config actions have been written to respond to changes in these values.

With larger overclouds, this metadata polling will cause noticeable load on the undercloud, especially nova-api and neutron (for port lookups).

I propose that we treat this collector as immutable, so ec2 data is collected once, and subsequent collection runs will just return if ec2.json exists.

[Steven Hardy (shardy)]

This sounds reasonable, although only for ec2 metadata (I don't think occ collects the native nova metadata does it, because that's not immutable, the key/value pairs can defintely be updated)

Considering the variety of performance challenges we face, this seems like a fairly easy incremental gain, so +1 - I'll target it at rc1 and we can see if a fix can be landed by newton, thanks!

[Steven Hardy (shardy)]

https://review.openstack.org/#/c/364021/ landed

[Steven Hardy (shardy)]

Since the fix was reverted I'm going to re-target this to Ocata-1, provided Steve is OK with that, hopefully that will enable a bit more time to fully test the fix before re-landing any revised patch.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/os-collect-config 5.0.0.0rc2 release candidate.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/os-collect-config 5.0.0 release.

[Steven Hardy (shardy)]

https://review.openstack.org/#/c/384712/ landed

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/os-collect-config 6.0.0.0b1 development milestone.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/os-collect-config 5.0.0 release.